Analyte testing systems

ABSTRACT

The present invention includes analyte measurement systems, analyte measurement meters, analyte testing devices, cartridges thereof and integrated circuits for use therewith, and further includes methods related to the use of the integrated circuits and, in certain embodiments, to the counting or tracking of parameters related to the cartridges and analyte test devices.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication Ser. No. 61/099,184, filed on Sep. 22, 2008, and is relatedto U.S. patent application Ser. No. 10/837,886 published asUS2005/0245844; Ser. No. 10/899,773 published as US2006/0024774; Ser.Nos. 11/830,760; 11/830,779; 11/830,786; 11/831,706; 11/535,985;11/535,986 published as US2007/0079783; Ser. No. 11/035,131 published as2005/0164322, Ser. No. 11/831,649 published as 2008/0033318, Ser. Nos.11/868,762, 11/350,398, 12/035,348, 11/830,770, 10/701,993 published as2004/0138588, Ser. Nos. 12/185,116; 12/185,117; 12/233,584 and12/185,118; as well as PCT applications PCT/US2005/014855; WO2006/19665;WO2008/39946; and WO2008/39949; and EP1779109; which are each assignedto the same assignee as the present application and are herebyincorporated by reference.

FIELD OF THE INVENTION

The invention relates to analyte testing systems, and particularly tomanaging information relating to analyte test strips and/or containersthereof. Such information may include expiration criteria for the stripsfor maintaining along with unique identifiers for the strips and/orcontainers of strips.

BACKGROUND OF THE INVENTION

There are a number of instances when it is desirable or necessary totest or monitor the concentration of an analyte, such as glucose,lactate, or oxygen, for example, in bodily fluid of a body. Bodilysample analyte tests are routinely conducted in a variety of medicalsettings (e.g., doctor's office, clinic, hospital, by medical personnel)and in the home by the patient and/or a caretaker. For example, it maybe desirable to monitor high or low levels of glucose in blood or otherbodily fluid that may be detrimental to a human. In a healthy human, theconcentration of glucose in the blood is maintained between about 0.8and about 1.2 mg/mL by a variety of hormones, such as insulin andglucagons, for example. If the blood glucose level is raised above itsnormal level, hyperglycemia develops and attendant symptoms may result.If the blood glucose concentration falls below its normal level,hypoglycemia develops and attendant symptoms, such as neurological andother symptoms, may result. Both hyperglycemia and hypoglycemia mayresult in death if untreated. Maintaining blood glucose at anappropriate concentration is thus a desirable or necessary part oftreating a person who is physiologically unable to do so unaided, suchas a person who is afflicted with diabetes mellitus.

The most important factor for reducing diabetes-associated complicationsis the maintenance of an appropriate level of glucose in the bloodstream. The maintenance of the appropriate level of glucose in the bloodstream may prevent and even reverse some of the effects of diabetes.Certain compounds may be administered to increase or decrease theconcentration of blood glucose in a body. By way of example, insulin canbe administered to a person in a variety of ways, such as throughinjection, for example, to decrease that person's blood glucoseconcentration. Further by way of example, glucose may be administered toa person in a variety of ways, such as directly, through injection oradministration of an intravenous solution, for example, or indirectly,through ingestion of certain foods or drinks, for example, to increasethat person's blood glucose level.

Regardless of the type of adjustment used, it is typically desirable ornecessary to determine a person's blood glucose concentration beforemaking an appropriate adjustment. Typically, blood glucose concentrationis monitored by a person or sometimes by a physician using an in vitrotest that requires a blood sample. The blood sample may be obtained bywithdrawing blood by lancing a portion of his or her skin, using alancing device, for example, to make blood available external to theskin, to obtain the necessary sample volume for in vitro testing. Thefresh blood sample is then applied to an in vitro sensor, such as ananalyte test strip, which is positioned in a meter or the like,whereupon suitable detection methods, such as calorimetric,electrochemical, or photometric detection methods, for example, may beused to determine the person's actual blood glucose level.

Available self-monitoring analyte systems generally include an analytemeter having a receptacle for receiving a cartridge containing aplurality of disposable analyte testing devices, e.g., test strips,which are individually and automatically dispensed on demand. An analytetest strip includes one or more chemical reagents designed to interactwith a target analyte(s) in body fluid applied to it in such a way thatan analyte meter connected to electrodes of the test strip can derive avalue of the level of the target analyte contained in the body fluid.The meter may be an integrated device which provides a lancing functionin addition to measuring the level of target analyte(s) in the bodyfluid being tested. Where the analyte test strips provide only a testcomponent, the lancing is performed by a separate lancing mechanismhoused within the meter. In other systems, the test strip may beintegrated with a lancet into a single component, such as disclosed inU.S. patent application Ser. No. 12/488,181, herein incorporated byreference in its entirety. In either variation, the meter is configuredto dispense the testing devices from the cartridge one at a time, asneeded.

The test strip cartridge may include a biasing member at a loading endof the cartridge to bias the contained test strips towards thecartridge's strip-dispensing end. A seal is typically provided at thecartridge's strip-dispensing end for minimizing exposure of the teststrips within the cartridge to ambient air. The seal is typically madeof an elastomeric material configured to be released temporarily topermit loading of a test strip from the cartridge to within the meterfor the lancing and testing processes. A desiccating material may beprovided separately within the cartridge or integrated into thestructural support of the cartridge to help maintain the analyte testdevices substantially free of moisture. An advantage of an automatictest strip cartridge is that numerous analyte tests may be performedwithout having to manually load a new test strip for each testperformed.

Examples of integrated lancing and testing systems are described in U.S.patent application Ser. Nos. 10/629,348, 10/701,993, 10/837,886,10/899,773, 11/035,131, 11/146,897, 11/160,407, 11/160,427, 11/350,398,11/535,985, 11/535,986, 11/830,760, 11/830,770, 11/830,779, 11/830,786,11/831,649, 11/831,706, 11/868,762, 11/870,420 and 12/035,348, thedisclosures of which are herein incorporated by reference.

Due to certain lot-to-lot inconsistencies in the test strip fabricationand manufacturing process, there may be variations in test stripsensitivity between lots which require some form of system calibrationfor each batch of strips. Currently, existing calibration mechanismsrequire the use of a calibration strip by the user, the inputting of acalibration code by the user, or the use of a machine readable mechanismon the strip or cartridge to modify the reaction interpretation of themeters for a particular lot of test strips.

Despite means for calibrating meters for given test strip lots, if atest strip is past its expiration date or its chemistry has otherwisedegraded due to humidity and other constituents of the ambientatmosphere to which it has been exposed subsequent to fabrication andpackaging and prior to actual use, i.e., during the test strip'sshelf-life, unpredictable and unreliable analyte test results arelikely. Moreover, during actual active use of a test strip cartridge,the cartridge is opened and closed by the meter each time a test stripis used, exposing the remaining test strips to an even higher level ofambient air, thereby contributing to degradation of the strips, even inthe presence of a desiccating material within the cartridge.

SUMMARY OF THE INVENTION

The present invention includes analyte measurement systems, analytemeasurement meters, analyte testing devices, cartridges thereof andintegrated circuits for use therewith. The subject integrated circuitscontain information and algorithms specific to the analyte testingdevices contained within a cartridge. The meters are configured tocommunicate with the integrated circuit wherein such device-specificinformation and/or algorithms may be transferable between a meter andthe integrated circuits. The present invention further includes methodsrelated to the use of the integrated circuits and, in certainembodiments, to the counting or tracking of parameters related to thecartridges and analyte test devices.

These and other objects, advantages, and features of the invention willbecome apparent to those persons skilled in the art upon reading thedetails of the invention as more fully described below.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is best understood from the following detailed descriptionwhen read in conjunction with the accompanying drawings. It isemphasized that, according to common practice, the various features ofthe drawings are not to-scale. On the contrary, the dimensions of thevarious features are arbitrarily expanded or reduced for clarity.Included in the drawings are the following figures:

FIG. 1 illustrates a distal perspective view of an exemplary meter of ananalyte monitoring system of the present invention;

FIGS. 2A and 2B illustrate distal and proximal views, respectively, of acartridge containing a plurality of analyte testing devices usable withthe analyte meter of FIG. 1;

FIG. 3 illustrates an exemplary analyte measurement system of thepresent invention in which the cartridge of FIGS. 2A and 2B isoperatively positioned within the meter of FIG. 1;

FIGS. 4A and 4B are side cross-sectional views of the analytemeasurement system of FIG. 3 which illustrate an operational sequence ofthe system; and

FIG. 5 provides an exemplary Calibration Log usable with the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

Before the present invention is further described, it is to beunderstood that this invention is not limited to particular embodimentsdescribed, as such may, of course, vary. It is also to be understoodthat the terminology used herein is for the purpose of describingparticular embodiments only, and is not intended to be limiting, sincethe scope of the present invention will be limited only by the appendedclaims.

Where a range of values is provided, it is understood that eachintervening value, to the tenth of the unit of the lower limit unlessthe context clearly dictates otherwise, between the upper and lowerlimit of that range and any other stated or intervening value in thatstated range, is encompassed within the invention. The upper and lowerlimits of these smaller ranges may independently be included in thesmaller ranges, and are also encompassed within the invention, subjectto any specifically excluded limit in the stated range. Where the statedrange includes one or both of the limits, ranges excluding either orboth of those included limits are also included in the invention.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. Although any methods andmaterials similar or equivalent to those described herein can also beused in the practice or testing of the present invention, the preferredmethods and materials are now described. All publications mentionedherein are incorporated herein by reference to disclose and describe themethods and/or materials in connection with which the publications arecited.

As used herein and in the appended claims, the singular forms “a,”“and,” and “the” include plural referents unless the context clearlydictates otherwise. It is further noted that the claims may be draftedto exclude any optional element. As such, this statement is intended toserve as antecedent basis for use of such exclusive terminology as“solely,” “only” and the like in connection with the recitation of claimelements, or use of a “negative” limitation.

The publications discussed herein are provided solely for theirdisclosure prior to the filing date of the present application. Nothingherein is to be construed as an admission that the present invention isnot entitled to antedate such publication by virtue of prior invention.Further, the dates of publication provided may be different from theactual publication dates which may need to be independently confirmed.

The invention is now described in greater detail with respect to thesystem of FIGS. 1-4; however, such embodiment is merely exemplary as thefeatures, advantages and objectives of the present invention apply toany type of analyte measurement system. The particular systemembodiments described herein are particularly suitable for glucosemeasurement applications; however, the present invention may be used inany analyte measurement application.

Referring now to the figures, FIG. 1 provides a distal perspective viewof a diagnostic device or meter 10 of the present invention. Whenreferring to “distal” and “proximal” with respect to the components ofthe subject analyte systems and analyte testing devices, the term distalrefers to the end which faces towards, contacts or is closest to theuser's skin when in operative use and the term proximal refers to theend which faces away from or is furthest from the user's skin when inoperative use. The exterior of meter 10 includes a housing 12 and acartridge door 14 at a proximal end of the meter. Housed within door 14under cover 46 are one or more batteries which provide power to theelectronics and electronic motors which operate the device. Housing 12contains various component assemblies of mechanical and electroniccomponents, including but not limited to various components for directlyinterfacing with a cartridge 40, shown from distal and proximalperspective views in FIGS. 2A and 2B, respectively. Cartridge 40contains a plurality of unused analyte testing devices, i.e., eithertest strips or strip-lancet combination devices (i.e., where the testingcomponent and lancing component are at opposing ends of the “strip”).Reference to “strip” or “test strip” herein refers to eitherconfiguration.

The meter's mechanical components include various gears and motors formoving and orienting the analyte testing devices, to various operativepositions relative to the housing. The electronic components includevarious printed circuit boards having circuitry for storing electronicdata and running software programs for controlling and operating thedevice and measuring the target analyte in the extracted bodily fluid.On one side of meter 10, housing 12 frames a display 16, a navigationkeypad 18 and a trigger button 20 which enable a user to interface withand operate the device. The various sidewalls of housing 12 framevarious apertures including aperture 22 for receiving a cartridge doorrelease latch 24, a test strip ejection slot 26, a recessed aperture 28for receiving a thumb wheel 30 for adjusting the depth of a fluidexpression cap or ring 32, and a switch 36 to disable or lock the meteragainst accidental button pushes when not in active use. Expression ring32 is configured for engaging with a finger or other lancing site on theuser's body to facilitate the expression of bodily fluid, e.g., blood,from the skin. A small test port 34 resides within expression ring 32through which a lancet or lancet end of a strip (not shown) is advancedand retracted. The expression cap 32 resides within and is carried by aframe structure (not shown) which is mechanically coupled to a thumbwheel 46. Rotating thumb wheel 46 adjusts the vertical height ofexpression ring 32 relative to the lancet when in a lancing position. Asthe lancing stroke of the lancet is fixed, adjusting the relative heightof the expression pad adjusts the location of the skin surface relativeto the lance stroke allowing variable lancing depths to accommodate, forexample, blood extraction at different sites on the body which mayrequire varying lancing depths. An electronic communications port (notshown) may also provided by which an on-board microprocessor is accessedfor programming, software download and off-board control.

As shown in FIG. 3, the meter's cartridge door 14 opens to an interiorcompartment 38 in which the replaceable test strip cartridge 40 of FIGS.2A and 2B is mechanically and electronically nested within meter 10. Thecartridge door structure 14 contains a spring-loaded piston 42 whichresides within the rectangular frame 44. A coil spring (not shown), forexample, biases piston 42 which in turn, when door 14 is closed on thecartridge 40, biases the proximal end 50 of the cartridge downwardagainst a tub 48, as shown in FIG. 4A, to create a hermetic seal at thecartridge's distal or strip-disposing end 52. An elastomeric seal 54,such as an O-ring type seal, may be provided around end 52 to furtherensure the hermetic seal. When meter 10 is not in use or is in aninactive state, as shown in FIG. 4A, tub 48 is seated againstelastomeric seal 54 by means of a lever 64, and the contained teststrips are substantially protected against the ambient environment. Whenthe meter 10 is activated to perform an analyte testing sequence, lever64 briefly lowers tub 48, as shown in FIG. 4B, to allow for a singletest strip or strip-lancet device 60 to exit the distal end 52 ofcartridge 40 onto a positioning element 62, which centers the strip forprecision loading onto a track 68, while the remaining unused teststrips remain in the cartridge. For this brief amount of time, thecartridge is not sealed and the contained test strips are exposed toambient air. A mechanism for sealing the cartridge upon removal from themeter may also be provided. In one embodiment, a spring-loaded latch maybe provided with the cartridge. The latch may be mechanically openedwhen the cartridge is installed into the meter. The latch may springshut sealing the cartridge when the cartridge is removed from the meter.Alternatively, the latch may be manually closed with or without theassistance of a spring. In another embodiment, a separate sealingattachment may be provided to a user who may install the attachment toseal the cartridge upon removal from the meter. In any of these ways,effects of exposure to ambient air may be mitigated during the time thatthe cartridge is removed from the meter.

Upon the release of an unused test strip 60 from cartridge 40, a pushermechanism 66 residing within track 68 engages the test strip andadvances it into a slot within rotatable turret 56 which, as shown inFIG. 4B, is aligned horizontally for receiving a test strip from thedistal end 52 of cartridge 40, which horizontal position also aligns theslot with strip ejection port 26 for ejection after the analyte analysishas been completed. Once within slot 56, strip 60 is in electricalcontact with the meter's electronics. Turret 56 is then rotated 90° orto the extent necessary for axial alignment with the lancet drivingmechanism 74. In embodiments where the testing component and lancet areintegrated within a single strip, a blade or lever 72 is then drivendownward for uncapping a lancet. The lancet or lancet end of the stripis advanced through test port 34 for lancing the skin. The strip is thenretreated and is rotated or flipped by 180° (or as necessary) as itremains within the turret slot 56. The test strip or the testing end ofthe strip is then advanced again through the port 34 again and is madeto contact the expressed bodily fluid, e.g., blood. The signal generatedby the electrochemical interaction between the strip's sensing chemistryand the target analyte, e.g., glucose, is received by the meterelectronics and the evaluated to provide the level of analyte in thefluid sample. The lancet cap may then be recapped over the lancet, ifapplicable. After testing, the strip is rotated 90° (or as necessary) toalign with and be ejected through ejection port 26. Pusher 66 may beused a second time for assisting in the ejection of the used andrecapped strip

Referring back to FIG. 3, in addition to applying a bias to cartridge40, the spring loaded piston 42 within cartridge door 14 simultaneouslyserves as the electrical interface between meter 10 and cartridge 40 byway of a plurality of electrical contacts 46 which electrically couplethe meter electronics with an integrated circuit (IC) 80, e.g., EEPROMor the like, which is sometimes referred to as a “smart chip.” Chip 80is mounted to the external proximal end 50 of cartridge 40; however, itmay be mounted at any suitable location on cartridge 40. In otherembodiments, chip 80 may be located internally to the cartridge or on atest strip contained therein, and may interface with meter 10 via RF orother wireless or optical communication means.

The smart chip 80 includes non-volatile memory storage for storing andcommunicating information and data about the test strips and/orcartridge 40 to the meter 10, including but not limited to test stripserial and batch numbers, date and time of manufacture, expiration date,etc. Also stored on chip 80 are one or more algorithms for calibratingmeter 10 to properly analyze fluid samples applied to the enclosed batchof test strips. The system is further programmed to separately trackinformation for different strips or groups of strips, such as may becontained in cartridges, vials or other types of containers of analytetest devices. As an associated chip distinguishes each cartridgecontainer of strips, a meter may discriminate between different groupsor containers of strips by reading the chip each time the meter ispowered-up to perform a glucose test using a strip from a certaincontainer or cartridge of strips.

Strips are manufactured in lots within which the strips have the same orsubstantially similar chemistry. Strips of different lots, however, maydiffer significantly which is why the lot information may be providedfor each cartridge of strips. As lots of strips are produced, the smartchip information may be customized accordingly. This provides theflexibility to support on-going changes in strip design. For example, ifan advantageous mediator for the strips is discovered, changes to thealgorithm that supports the new mediator can be made through changingthe parameters in the chip alone without having to modify the meter. Theprocessor chip may also be programmed to receive information from themeter about the meter itself, including, for example, the meter serialnumber, etc. The chip also includes processing components, such asclocks or counters, for example, for tracking the number of unusedstrips remaining in the cartridge and for timing various events, such asthe duration of time the cartridge is operatively positioned in themeter, tub open time, etc., many of which are described in greaterdetail below.

Given the importance of reliable glucose test results in a self-careregimen, the cartridges and/or meters may have one or more desiccatingcomponents to inhibit degradation of the test strips by moisture theymay be exposed to. As mentioned previously, when the cartridge isunsealed to remove a strip for testing, however, the strips remaining inthe cartridge are exposed to the ambient air. When the cartridge isagain sealed after removal of the strip for testing, the desiccatingcomponents dry out the inner cartridge to a state that continues untilthe cartridge is unsealed for another test.

The cartridge-specific processor chips of the present invention areconfigured to precisely track or count certain parameters which may varyover time and to track or clock time passage of certain conditions ofexposure to ambient air. The various counted/timed parameters may havean integer value, e.g., a number of strips, hours, days, etc. which iseither increased or decreased by 1 (or another integer as otherwiseprogrammed) upon the occurrence of a certain event, e.g., theperformance of an analyte test, or may be an accumulation of time, e.g.,in days, hours and/or seconds.

Various counted/timed parameters which may be provided by the subjectcartridge chips are now described in greater detail, many of which areprovided for the purpose of preventing the use of test strips which haveexpired due to the passage of time and/or due to the overexposure toambient air. The system/chip may be configured such that the meterand/or cartridge becomes inoperable when one or more of thesecounted/time parameters reach a maximum value. In other words,inoperability may be achieved by any one of the parameters reaching itsrespective maximum value or based on a summation of two or moreparameters at any given time. Alternatively, the meter and cartridge maycontinue to function upon a determination that the contained test stripshave expired, but the data obtained from analyte tests with theseexpired strips will be flagged by the system accordingly.

(1) Time Zero (T₀) is the designated baseline time programmed into thechip which may be the date/time of manufacture of the test strip lot,the date/time at which the cartridge is packaged, or the date/time thecartridge is first installed into a meter, or various starting times maybe employed depending on the counting/timing function employed. Many ofthe system's counting and timing algorithms are initiated at T₀.

(2) Expiration Time/Date counts or tracks the number of days (either asan integer or in days/hours/seconds) continuously from T₀ at which pointthe cartridge would become inoperable, or the meter would not be able toperform a test with any of the strips remaining in the cartridge.Alternatively, when the Expiration Time/Date is reached, the systemprovides an audio or visual warning to the user that indicates that anyfurther tests made with the remaining test strips may not be reliable,or would not incorporate such test results therefrom among thosecompiled for purposes of analytical reporting. In certain embodiments,there may be multiple expiration dates/times, e.g., a first time where awarning is provided that the test may be unreliable, a second time laterthan the first time where a test can be performed but with a warning andwhere the results are not kept for analytical graphs and/or logging, anda third time later than each of the first and second times where a testsimply cannot be performed with a strip from the expired cartridge. Oneor more additional expiration dates/times can be set that are sumperiods of heavy ambient exposure, i.e., having faster rates ofdegradation, as will be further described below. The system may beprogrammed to allow testing with expired strips, but preferably withuser confirmation of such.

(3) Tub Open Time counts, after insertion of the cartridge into themeter, the number of times the meter's tub is lowered or opened from thecartridge to load an analyte testing device (as in shown in FIG. 4B)and/or the accumulated time in which the tub is in the lowered or openedposition, i.e., the accumulated time which the contained test strips areexposed to ambient air. In certain embodiments, the systems areprogrammed to discriminate and separately track between periods ofvarying degradation rates. When test strips are directly exposed toambient air, i.e., when the tub is in the lowered or open position, thetest strips experience relatively faster rate of degradation as comparedto when test strips are sealed within a desiccated environment, i.e.,after a cartridge is removed from its packaging and placed within ameter, but with the tub in the up or closed position. Thus, the periodsof time during which the cartridge is unsealed are periods ofstrong/faster degradation, while the periods of time during which thecartridge is sealed and desiccated are periods of somewhat weaker/slowerdegradation.

(4) Usage Days counts the number of days a cartridge is used and may bemeasured continuously from either removal of the cartridge from itsoriginal packaging or upon insertion of the cartridge into a meter,whether or not the cartridge is removed (with one or more stripsremaining) and replaced into the same meter any number of times. Thesystem may be configured to presume that a cartridge is sealed duringthe entire time from manufacture to insertion into the meter. That is,the time from unsealing of a fresh cartridge until insertion and sealingwithin the meter may be neglected. Alternatively, the system may trackthis interim unsealed time for purposes of determining expiration thecontained test strips (see Cartridge Removed Time below). For example,an electrical connection may be broken when the cartridge is unsealedwhich initiates a counter or clock that is stopped when the cartridge issealed into the meter, or the time may be estimated by a user andmanually entered, or a timer may be started on the meter by the userwhen the fresh cartridge is about to be unsealed which is then stoppedlike a stopwatch when the cartridge is sealed within the meter. Thisinterim time may also be added to Tub Open Time or accounted forseparately as a period of strong degradation.

(5) Cartridge Removed Time may track any time between removal of thecartridge from the meter and its replacement back into the meter. Thismay be particularly relevant in embodiments where the cartridge does nothave a self-sealing mechanism, such as a latch or the like, that allowsit to be hermetically sealed (after removal from its hermetically sealedpackaging). An algorithm may be employed which adds the CartridgeRemoved Time to Tub Open Time for purposes of determining whether amaximum exposure threshold time has been reached. That is, the effect ofexposure of the analyte testing devices in the cartridge may be countedthe same whether the tub is open for an installed cartridge or thecartridge is removed from the meter. This time may also be added to TubOpen Time or accounted for separately as a period of strong degradation.As such multiple expiration clocks may be kept, wherein the cartridge isdeemed expired when the first of these runs out, or a combination may beused such as counting the periods of stronger degradation as having aweighted value, e.g., twice or three times the degradation effect ascompared to periods of weaker degradation. Alternatively, one or more ofthe counters/timers may be summed together or otherwise counting down toexpiration.

(6) Remaining Tub Open Time represents the total amount of time thestrips are still allowed to be unsealed while in the meter where acertain amount of Tub Open Time is counted down to expirationindependently of any other expiration tracking. This parameter may be aninteger in minutes and/or seconds which is decremented as the Tub OpenTime is incremented. When the Remaining Tub Open Time reaches zero, thecartridge will be expired (if it hasn't already expired due toexpiration based on total time from manufacture and/or total time sinceinstallation of the cartridge into the meter). A Current Tub Open Timemay also (or alternatively) be tracked representing the total amount oftime the strips have been unsealed while in the meter (and perhapsotherwise, see above).

(7) Analyte Testing Devices Remaining indicates the number of unuseddevices, e.g., test strips, which remain in the cartridge. The initialtotal number of device may be recorded onto the chip which number isdecremented each time a test strip is advanced out of the cartridge oreach time the tub is opened. Although the meter may not be able toperform a test when the cartridge is empty, the meter may still power-onto perform analyses and reporting functions, e.g., the user may reviewresults such as graphs and log entries. Examples of such are disclosedin U.S. patent application Ser. No. 12/233,584, which is incorporated byreference in its entirety.

(8) Allowable Days for Cartridge in Device represents the amount of timethe cartridge can be stored within the meter before the strips may bedeemed to provide unreliable or inaccurate results. This parameter maybe an integer of days. The cartridge may be deemed to expire when eitherthe Remaining Tub Open Time or the Allowable Days For Cartridge inDevice has expired, whichever is earlier, or some combination of thetwo, or including a time from manufacture of the cartridge as a thirdexpiration period that is kept separately or in combination with theothers.

(9) Error Detection/Correction/Data Integrity. An error detection and/orerror correction and/or data integrity protocol(s) may be employed. Forexample, a Cyclic redundancy check (CRC), or the like, may be performedperiodically or on-demand by the user to ensure the integrity of thedata stored on the chip or the chip's reader.

(10) Cartridge/Meter Unique Identifier. When a new cartridge isinstalled into a meter, a unique identifier of the meter, e.g., a serialnumber or the like, is transferred and recorded on the cartridge chip.This feature mitigates incorrect counting and tracking of parameters bypreviously or partially used cartridges. For example, when a partiallyused cartridge is installed in a meter, the meter identifier previouslystored on the cartridge chip is compared to the current meter'sidentifier. If they are the same, then the cartridge is the last oneinstalled and the various counted/time parameters can be updatedaccordingly. If they are not the same, then the cartridge is not thelast one installed on that particular meter and a new Cartridge Log(described in greater detail below) may be created and stored. Thesystems may also be configured such that the subject meters record andstore a unique identifier from each new cartridge installed into it andcreating a Cartridge Log for each unique cartridge identifier. Thesystem may also be configured to maintain a count of new cartridgesinstalled in the meter over its lifetime or for a designated period oftime, referred to as New Cartridge Count.

(11) Control Solution Range Delta provides the meter with theinformation necessary to determine the correct range for controlsolution test values for a particular lot of test strips. Any number ofthese range values, depending on the type of different control solutionsthat may be used to check the integrity of the test strips. For example,there may be three values, one for each of three possible controlsolutions. The meter will read the delta value for the control solutiontest selected and use it to adjust the expected range to determine ifthe measured value falls within.

(12) Cartridge Log. In addition to reading and modifying the cartridge'sprocessor chip, as described above, there may be a Cartridge Log createdin the meter's non-volatile memory for each cartridge installed in orderto optimize system performance. Additionally, certain of the cumulativecartridge data may be used to analyze user compliance history, trends,etc. FIG. 5 illustrates an embodiment of a Cartridge Log usable with thepresent invention where data (e.g., counts, clocked time, identifiers,and any of the parameters discussed herein) in the Log are assigned abyte number and recorded in bit format. Other information not listed inthe Log of FIG. 5 may also be stored in the log. A Cartridge Log may beupdated periodically, e.g., daily or with each analyte test performed bythe meter. If an installed cartridge is removed and then reinstalled ata later time, its original Cartridge Log data is updated or a newCartridge Log may be created with its status set to Used. Additionally,a partially used cartridge installed from another meter will generated anew Cartridge Log for that cartridge with a status identifier of Usedand Expired. When the meter's memory capacity designated for storingCartridge Logs becomes full, the oldest Cartridge Log may beoverwritten. Empty cartridges or cartridges with chips that cannot beread may not alter the Cartridge Log or the New Cartridge Count. Testresults obtained from tests conducted with expired strips may berecorded in the Cartridge Log, but are identified as coming from expiredstrips. The Cartridge Log may also be updated to include the date andtime the cartridge is removed.

(13) Calibration Algorithm/Code. The cartridge chip may further providea Calibration Algorithm which includes a calibration code and other datafor calibrating the meter to optimally perform for the particular lot ofanalyte testing devices contained within the cartridge. Alternatively,the Calibration Algorithm or Code may be separately provided on a barcode, a RFID tag, a label, or otherwise may be located on individualstrips contained in the cartridge or vial. U.S. patent application Ser.No. 11/350,398, incorporated by reference in its entirety, providesfurther examples of alternative embodiments for purposes of calibration.For example, there may be contact pads that may be shorted together orkept apart during a test strip manufacturing process in order tocommunicate a calibration code to the meter. Alternatively, there may bea set of contact pads and a varying resistance between the two padswhere the resistance is changed during the manufacturing process of thetest strips to communicate a calibration code to the meter. Thesealternatives may be provided along with an electrical memory that isreadable and writable by the meter, which communicates a calibrationcode to the meter, and can carry other information such as stripexpiration and/or a strip number count down and/or other featuresdescribed with regard to the smart chips of the present invention.

While the present invention has been described with reference to thespecific embodiments thereof, it should be understood by those skilledin the art that various changes may be made and equivalents may besubstituted without departing from the true spirit and scope of theinvention. In addition, many modifications may be made to adapt aparticular situation, material, composition of matter, process, processstep or steps, to the objective, spirit and scope of the presentinvention. All such modifications are intended to be within the scope ofthe claims appended hereto.

What is claimed is:
 1. A method of tracking at least one degradationparameter for analyte testing devices dispensable from within a sealedcartridge having an integrated circuit coupled thereto and installablewithin an analyte measurement meter communicable therewith, the method,upon installation of the cartridge within the meter, comprising:communicating with the integrated circuit and accessing the at least onedegradation parameter, the at least one degradation parameter comprisinga first degradation parameter comprising cumulative time the analytetesting devices are exposed to ambient air and a second degradationparameter comprising cumulative time the analyte testing devices areexposed to desiccated conditions, wherein the cartridge comprises adesiccating material; and updating the at least one degradationparameter based on at least one type of action performed by the meter,the at least one type of action comprising a first type of actioncomprising temporarily unsealing the cartridge and a second type ofaction comprising receiving the cartridge in the meter.
 2. The method ofclaim 1, further comprising decrementing a parameter stored on theintegrated circuit representing the number of analyte testing devicescontained in the cartridge.
 3. The method of claim 1, wherein theupdating comprises summing at least two degradation parameters.
 4. Themethod of claim 1, further comprising calibrating the meter according tocalibration parameters stored on the integrated circuit.
 5. The methodof claim 1, further comprising creating a modifiable log of informationabout the cartridge and the analyte testing devices contained therein.6. The method of claim 1, further comprising commencing the timing ofexpiry of the analyte testing devices.
 7. The method of claim 1, furthercomprising storing a unique meter identifier onto the integratedcircuit.
 8. The method of claim 1, further comprising storing a uniquecartridge identifier onto the meter.